1=pod
2
3=head1 NAME
4
5RAND_bytes, RAND_pseudo_bytes - generate random data
6
7=head1 SYNOPSIS
8
9 #include <openssl/rand.h>
10
11 int RAND_bytes(unsigned char *buf, int num);
12
13 int RAND_pseudo_bytes(unsigned char *buf, int num);
14
15=head1 DESCRIPTION
16
17RAND_bytes() puts B<num> cryptographically strong pseudo-random bytes
18into B<buf>. An error occurs if the PRNG has not been seeded with
19enough randomness to ensure an unpredictable byte sequence.
20
21RAND_pseudo_bytes() puts B<num> pseudo-random bytes into B<buf>.
22Pseudo-random byte sequences generated by RAND_pseudo_bytes() will be
23unique if they are of sufficient length, but are not necessarily
24unpredictable. They can be used for non-cryptographic purposes and for
25certain purposes in cryptographic protocols, but usually not for key
26generation etc.
27
28=head1 RETURN VALUES
29
30RAND_bytes() returns 1 on success, 0 otherwise. The error code can be
31obtained by L<ERR_get_error(3)|ERR_get_error(3)>. RAND_pseudo_bytes() returns 1 if the
32bytes generated are cryptographically strong, 0 otherwise. Both
33functions return -1 if they are not supported by the current RAND
34method.
35
36=head1 SEE ALSO
37
38L<rand(3)|rand(3)>, L<ERR_get_error(3)|ERR_get_error(3)>,
39L<RAND_add(3)|RAND_add(3)>
40
41=head1 HISTORY
42
43RAND_bytes() is available in all versions of SSLeay and OpenSSL.  It
44has a return value since OpenSSL 0.9.5. RAND_pseudo_bytes() was added
45in OpenSSL 0.9.5.
46
47=cut
48